The moment when Luis Suárez had just bitten Giorgio Chiellini of Italy but Barcelona still signed the Uruguayan. Photograph: Guo Yong/REX

Shirt off, wires on, thumbs up: it is the photograph that dominates the summer and it is the same every time, at every club and for every player. The new signing lies on a treatment table in front of a board bearing the sponsor's name, monitors suckered on to his bare chest, and grins. He raises a thumb or, if the photographer is particularly imaginative, two: the crack completes his medical. Like the bombastic presentation, the hospital shot is part of the ritual that every signing performs.

Except one. This year there was a picture missing: the summer's biggest signing was carried out almost clandestinely. "Luis Suárez is entirely our player," said Barcelona's sporting director, Andoni Zubizarreta. It appeared an odd remark but this was something he felt needed saying, as if reassurances were required, as if he had to reiterate that, yes, this transfer had really happened. After all, until then the new man had been the invisible man, stuck in a kind of surreal limbo.

Zubizarreta was speaking on the day that Barcelona had planned to present Suárez, at €81m (about £64m) officially the most expensive signing in their history. Fifa, though, had not allowed them to unveil him. And how appropriate that old cliche feels now: Suárez has remained "veiled" as if lurking under a sheet. We all know he is there but we have to pretend he is not. "We have been advised by our lawyers to be extremely prudent and not say anything," Zubizarreta said.

That morning, Wednesday 16 July, the Uruguayan had completed his medical at Barcelona's training complex in San Joan Despí but Fifa warned the club that no pictures must be published. No one was to talk about it and, as for him sticking his thumbs up, forget it. The ridiculousness of the ruling was, unlike Suárez's chest, laid bare.

Fifa banned Suárez for nine games with Uruguay and from "all football activity" for four months, meaning eight league games and three Champions League games for his new club. According to that ban, the earliest he will play for Barcelona is 26 October.

So far, so standard, depending on your opinion of the 20-game length of the ban. But beyond the significant size of the suspension, the question is whether Fifa has the jurisdiction to impose the rest of a vague blanket sanction, to have effectively marched Suárez out of the Uruguay team hotel and out of Brazil in the first place, as if it was the state, and then impose a ban on all "football activity", whatever that means. It is one of the questions that was asked at the court of arbitration for sport on Friday.

It did not mean stopping him signing – la pela es la pela as they say in Catalonia, money's money, and it might have drawn a potentially catastrophic legal challenge – but it did mean stopping anyone celebrating him signing or marking the occasion.

It means stopping him setting foot inside a football stadium or doing anything "football related". If someone kicks a ball Suárez's way on the beach, can he kick it back? Can he complete his Panini collection? What he does know is that he is not allowed to train with his team-mates until the ban is over, although he has been training alone, in a quiet, hidden corner of Catalonia.

Barcelona have asked the Cas if this amounts to a restraint of trade and argue that it is surely up to Barcelona who trains with them. At boardroom level they believe that not only is the size of the ban disproportionate but the club should not be punished for something that happened while Suárez was on international duty and belonged to another club, even if they recognise that they signed him knowing that.

Everything is on hold until the Cas delivers its verdict, which it intends to do "as soon as possible and probably before the end of next week". Supporters and media have waited outside the home of Suárez's parents-in-law in Castelldefels, just outside Barcelona, but he has dashed past them in silence. He has not said a word and he will not. He has not returned to the club's training ground. He went away, locally, on holiday but still on standby. "We have been advised to be very discreet," Zubizarreta said. Publicly it is as if he barely exists, hence Zubizarreta's reminder that he does and that he is theirs.

"It is not a tragedy," Barcelona's coach Luis Enrique said. "It is something that we already knew. The ideal situation would be to have all the players available to us from the start of the season but we were already counting on this handicap. The season is very long and there will be lots of games to see all the players. Sometimes you don't get what you want, you get what you're given. And this is one of those times."

Yet Suárez's absence and the fact that he cannot train with his team-mates increase the doubt and uncertainties that hang over Barça as they head into a new season. How do you construct a machine without one of the most important parts, perhaps the most important part? Suárez symbolises the shift in style, a change in the philosophy of which Barcelona made so much: an €81m signing who breaks the mould.

"I'm delighted with the signing of Suárez; the more good players, the better," Luis Enrique said. He pushed for the transfer, convincing Zubizarreta because he saw in the Uruguayan someone who can infuse the team with a competitiveness that has been lacking. It is tempting to see boardroom influence in play too: they needed a major signing and they, not Real Madrid, got Suárez. But the wait to see what the team look like will be extended; the wait to construct and fine-tune it will too.

It is an important delay for a new model at a club where the president, Josep Maria Bartomeu, had already talked about a "profound" change. One director speaks for many when he mentions the need for Barcelona to be "tougher", more aggressive. Much like their new manager, in fact: a feisty, ultra-competitive player who crossed the clásico divide and publicly, pointedly, proclaimed that he had finally found his place.

Luis Enrique, who competes in iron man competitions and triathlons, played at Barcelona and coached their B team to success, following a pattern that was familiar. He was close to Pep Guardiola but their personalities are different and, on the face of it, many believe that their styles will be too. And yet, it is not so much a case of escaping Guardiola as recovering those vital elements of the Guardiola style that have been lost over the past two years.

"I want a team that is faithful to the Barcelona we have seen [recently], the one that won everything. A team that plays to win at home and away, that scores goals and defends well, that is attractive," Luis Enrique said. The new manager talks about fidelity to the "identity" of the club but he also spoke of the need to avoid being "predictable", to find "different ways of making life difficult for our opponents", and this is certainly a different era at the Camp Nou. They have a new coach, new players, even a new physiotherapist. Thirteen players have left, nine have arrived already.

So far they have spent more money and received more money than any other team in Europe. Two goalkeepers have arrived, Marc-André ter Stegen and Claudio Bravo. Ivan Rakitic joined. They have even signed two centre-backs. Jérémy Mathieu, originally a left-back successfully converted to the middle, has joined from Valencia for €20m (£15.8m), while Thomas Vermaelen has joined for €18.8m (£15m) from Arsenal. In total Barcelona have spent €169m (£130m), dictated partly by the fact that what Barcelona are building now is not just for this season but for next season too: the ban on transfer activity for breaking rules relating to the signing of youth team players has been suspended, not overruled.

Cesc Fábregas departed and so did Alexis Sánchez, fetching almost €80m (£63m) between them. Of the three club captains, two have left – Carles Puyol and Víctor Valdés – and the third, Xavi Hernández, is sticking around for now, his move to New York put on hold.

Xavi is likely to play a reduced role. He has been the player imposing a style, an idea, on the team. A search for the new Xavi may have led, logically, to the conclusion that there is no such thing. Better to evolve – and in Andrés Iniesta and Lionel Messi they have players who can play a part in manning that controlling mission, while Sergio Busquets may even advance – than to employ an unconvincing copy.

The fact that Javier Mascherano did not leave and appears set to return to his original position in midfield also hints at the shift in style, as does the signing of Rakitic from Sevilla. He was one of the outstanding players in Spain last season but he is not a "Barça-style" midfielder. There is a touch of the Luis Enrique in him, though.

It may be that Messi plays a deeper, more creative role; signing a striker makes more sense that way. Although Suárez could theoretically simply replace Alexis in the line of three, he, Neymar and Messi occupy broadly similar spaces. Other strikers have arrived and left again, in part because of Messi: Zlatan Ibrahimovic and David Villa could both have laid claim to be the continent's best striker, but both played supporting roles that at times did not entirely satisfy. For the first time there are hints that he is receptive to a shift and the Argentinian may change from false No9 to real No10. He has scored more goals than anyone else in Spain over the last six years but he has provided more assists too. Maybe it is time for the balance to tilt a little further; it is certainly something that Luis Enrique has contemplated. In front of Messi he would have a striker who complements him well.

Messi won last year's Golden Boot; this year's joint winner, with Cristiano Ronaldo, was Luis Suárez. Now Messi and Suárez will play together. Well, not now exactly. Now, they cannot even train together. But maybe on 26 October, the day after Suárez's ban comes to an end and when, conveniently enough, Barcelona are due to face Real Madrid for the first time in the new season and a new era.